Abrasive article and method of manufacturing the same



30 of making such articles, which contain finely superior for ce'i'tain uses such as thesharpemng 30 35 consisting essentially of a mass of organic bondattached to the mass of cast material 35 '50 I will now describe the invention by reference After drying until the alcohol odor. is absent, this 50 $5 the invention.- I incorporating heat hardenable phenolic rain 66 UNITED STATES PATENT OFFICE ABRASIVE ARTICLE AND METHOD OF MAN- UFACTURING THE SAME Norman P. Robie, Niagara Falls, N. Y., ammo:

to The Carborundum Company, Niagara Falls, N. Y a corporation oi Delaware No Drawing. Application February 2, 1937, Serial No. 123,728

4 Claims. (Cl. 51-278) This invention relates to improved abrasive Example I articles and methods of manufacturing the same. More specifically, the invention is concerned with 275 gram; of polymerrlfifddvmyl gi i abrasive or polishing articles consisting of. a mass solved in 82 grams of a y was me co 1240 grams of finely pulverized levigated alumina 22 .1 g :gi g figgfigfi ggfigg finely dmded is uniformlysuspended in the solution by stirring. 5

Bonded abrasive products, as typified by abra- A catalyst cumming of 3 gram-5 of metallic 'sive wheels and distinguished from coated abra- Sodium reacted ill-100 Of nhydrous methyl sive products such as are commonly referred to as alcohol stirred into the suspension uni omuy sandpaper, maybe divided into two general and the mlx is quickly mured into a mold 1 10 classes. One of these classes comprises the ord.i-'- In about five minutes gel polyvinyl alcoho nar rindin wheel, the ma function with levigated alumina in suspension is formed, whi ch is to emove materi al qu itities of the the polyvmyl alcohol being formed substltu' work being treated, while the other subdivision mm of i: on groups i gg tincludes lishin articles, the rima ose the ace e groups 0 e p0 ace 15 of which i to d velop finish wlEile the g lt naval fi acetate is formed along with the polyvinyl of material is a secondary consideration. Articles a co oi the first class are usually rather porous in i E i 3; fi g it character to provide clearance spaces for the n O F s I g material which has been abraded and to assist time which may ast abou r y or 20 breakdown of the article in use as the abrasive accordmg to the drying conditions present' particles on the su'rface of the article become mixgure a alcolziol g rfig igfig dulled. Polishing articles, on the other hand, g 53 d e l r are comparatively dense and may, in effect, be 6 g g b a 3 consideredasamass of bonding material containt at t 9 8 5 evapora e n o e 25 atmosphere. igi gfif i mashing particles embedded The block thus formed is drilled and machined by the usual known methods and machined into The present invention is concerned with im- 1 proved articles of this second class and methods the form of a wheel which will be found to be of razor blades. figfigg g ggmzg gg and to In an alternative method the mixture is poured It is accordingly an object of. the invention to amund 'i g z gfi 1 is provide improve'dabrasive or polishing articles dry t 15 mm a e at y 'ing material having abrading or polishing par- Example H ticles distributed therethrough. A further object of the invention is the provision of methods of 7 3mm 0 po e d v y c e 0 manufacturing such articles.- solved in 550 grams of anhydrous methyl alco- 40 The method of the invention consists essenhol. 1240 grams of 400 mesh silicon carbide are 40 tially in first preparing a suspension of finely stirred into the soluttion. 100 grams glycerine divided particles in a liquid which is adapted to diluted with 100 grams methyl alcohol are slowly be solidified to form a mass of organicmaterial stirredin.

, carrying finely divided polishing particles dis- A catalyst consisting of 3 grams metallic soditributed uniformly in the mass. There are a um reacted in cc. of anhydrous methyl alco- 45 number of types of liquids which can be used hol is stirred into the suspension. A gel quickly and the particular method employed in carrying formed from which the volatile methyl alcohol out the invention depends specifically onthe and methyl acetate evaporated, leaving the glyccharacter of the liquid material employed. erin as a plasticizer for the polyvinyl alcohol.

to a number of specific examples; It is to be mass is tough and leathery. Thin shoes are flexunderstood that these examples are given ;for ible and very suitable for hand polishing brass the purpose of illustrating the invention and and other metals.

'are'not intended to be limitative or the scope of. The polyvinyl alcohol gels may be modified by dissolved in methanol in the methanol solution of polyvinyl acetate. A sodium methylate catalyst may be used to cause gel formation. The presence of the phenolic resin slows the reaction at room temperature. The reaction, however, may be speeded by refluxing the mixture until the gel formation starts and the mixture may then be poured into suitable molds for the completion of the gel formation. The resulting gel with. abrasive in suspension may be dried and baked to harden the mixture. The phenolic resin in the gel after baking hardens and ins'olubilizes it. p

While the use of very fine abrasives has been illustrated in the examples, this invention is in no way limited to the use of very finely divided material. Coarser abrasives may be used but it is desirable to thicken the viscosity of the solution and solidify the solution quickly to prevent settling of the abrasive.

Other modifications employed in the manufacture of abrasive products may also be employed. Such modifications include the. use of modifying agents to alter the characteristics of the organic material. Such modifying agents include, for example, plasticizing agents to increase the elasticity of the bond and filling materials. Insolubilizing treatments such as the inclusion of compatible insolubilizing agents to the mix or treatment after gelation as by exposure to the fumes of a volatile aldehyde may also be employed.

Abrasive products made inaccordance with the invention have been found to be particularly well adapted for polishing operations such as the final finishing of safety razor blades or steel rolls used in the final rolling of sheet materials.-

While I have illustrated the invention by reference to a number of specific examples, it is to be understood that the invention is not limited to the materials and methods therein described but may be otherwise practiced as defined by the appended claims.

I claim:

1. In a method of making abrasive articles, the steps which comprise preparing a. suspension ,of abrasive particles in a solution of a polyvinyl ester in an alcohol and adding a catalyst to cause reaction between the alcohol and the ester, whereby there is formed a solid mass of polyvinyl alcohol containing abrasive particles suspended therein and distributed uniformly therethrough.

2. The method of making an abrasive article consisting essentially of a binder and an abrasive material which comprises suspending finely pulverized abrasive material in a solution of polymerized vinyl acetate in an alcohol and adding a catalyst to cause a reaction whereby there is formed a dense solid mass of polyvinyl alcohol carrying the abrasive material uniformly distributed therethrough.

3. A method oftmaking abrasive articles which comprises the steps of dissolving polymerized vinyl acetate in anhydrous methyl alcohol, stirring finely pulverized levigated alumina into the solution thus formed, adding to the solution a catalyst consisting of metallic sodium reacted in anhydrous methyl alcohol, and allowing the mixture to set until a polyvinyl alcohol gel thus formed has hardened.

4. method of making abrasive articles comprising the steps of dissolving polymerized vinyl acetate in anhydrous methyl alcohol, stirring finely pulverized abrasive into the solution thus formed, and adding a catalyst to cause a reaction and thus form a gel of polyvinyl alcohol, with the abrasive particles uniformly suspended therein, I

NORMAN P. ROBIE. 

